1. Field of the Invention
The present invention relates to a gas laser device which generates or amplifies laser light by applying a high frequency voltage across electrodes to achieve a discharge, and more particularly to a gas laser device designed to make the power density between the electrodes uniform by using a dielectric.
2. Description of the Related Art
FIG. 18 shows an outline of the configuration of a conventional cross-flow gas laser device. In FIG. 18, a pair of dielectric electrodes 1 are placed face to face sandwiching the discharge gap 2 through which the laser gas circulates in the direction indicated by the arrow A. The dielectric electrodes 1 are made by covering electrode means 3, which has a shape elongated in the direction orthogonal to the laser gas flow (the direction orthogonal to the surface of the page), with a dielectric shell 4. if a high-frequency voltage from a high-frequency power source 5 is applied across the electrode means 3 in a cross-flow gas laser device which has been made in this way, then the laser gas flowing through the discharge gap 2 is stimulated and laser light is generated in the direction perpendicular to the surface of the page by providing a resonator in a direction perpendicular to the surface of the page, though this is not depicted here. In this case, the presence of the dielectric shell 4 around the electrode means 3 makes the power density in the discharge gap 2 uniform, allows a homogenous discharge and gives a stable laser output.
The frequency of the high-frequency voltage applied across the electrode means 3 needs to be raised to at least 700 kHz if the laser oscillation is to be made more efficient. However, there are problems in that, if the output frequency of the high-frequency power source 5 is raised, the discharge is needlessly dispersed to either side of the electrode means 3 due to capacity coupling via the dielectric shell 4 which covers the electrode means 3, and, as a result, it is difficult to improve the laser oscillation efficiency sufficiently even though the output frequency of the high-frequency power source 5 has been raised.
Further, in some cases, there are also problems that the laser oscillation efficiency will be reduced completely counter to what was initially intended.